Pneumatic level sensing device

ABSTRACT

This device relates to a level sensing assembly useful in card or document transport systems. Fluid pressure is supplied to various orifices and interact therein. As cards or documents are stacked, the cards interrupt the flow of fluid thereby producing output control signals. Orifices are placed one above the other thereby enabling the output signals to control a lowering, raising or feed device to keep the level of the documents between the orifices or at a predetermined level.

United States Patent Gluskin [451 May 30, 1972 [54] PNEUMATIC LEVEL SENSING DEVICE [72] Inventor: Richard S. Gluskin, Wayne, Pa.

[73] Assignee: The United States of America as represented by the Secretary of the Army 22 Filed: Aug. 17,1970

21 Appl.No.: 64,521

[52] U.S. Cl. ..271/56, 271/62 R [51] Int. Cl ..B65h l/l8 [58] Field ofSearch ..271/62, 88,56, 25,31; 137/815 [56] References Cited UNITED STATES PATENTS 2,902,278 9/1959 Bradshaw ..271/62 X 2,707,142 4/1955 Waite ..271/88 X Reader et al l 37/8l.5 9/1970 Thorburn l 37/8l.5 X

Primary Examiner-Evon C. Blunk Assistant Examiner-Bruce H. Stoner. Jr.

Attorneyl larry M. Saragovitz, Edward J. Kelly, Herbert Berl and Milton W. Lee

[57] ABSTRACT This device relates to a level sensing assembly useful in card or document transport systems. Fluid pressure is supplied to various orifices and interact therein. As cards or documents are stacked, the cards interrupt the flow of fluid thereby producing output control signals. Orifices are placed one above the other thereby enabling the output signals to control a lowering, raising or feed device to keep the level of the documents between the orifices or at a predetermined level.

3 Claims, 6 Drawing Figures PATENTEDmso I972 3,666 263 PlezA 1 INVENTOR I 6 3A RICHARD 's. GLUSKIN mm M ATTORNEYs BACKGROUND AND SUMMARY OF THE INVENTION This invention relates to the broad field of fluid sensing devices and more particularly to pneumatic sensing devices useful in document or card transport systems for maintaining stacked documents at a predetermined level.

Various prior art devices have been developed, including pneumatic proximity sensing devices, but such devices employ moveable sensing parts and/or various shaped parts, somewhat elaborate control systems and are unsuitable for use as document level sensing means. The device described herein is a pneumatically operated unit that senses the level of a stack of documents, and if desired, generates pneumatic signals to initiate appropriate control action. The device has no moving parts thereby offering reliable operation. Its simple design will allow it to be injection molded from plastics thereby making it inexpensive.

Sensing channels are positioned one above the other in such a manner as to allow fluid under pressure to pass therethrough. Fluid flow through the channels is interrupted by a transverse fluidic pressure. As documents are stacked, their increasing height blocks off the flow of the transverse fluidic pressure thereby permitting unrestricted flow through the sensing channels to provide signals of relative height to a document leveling, raising, or feeding device.

BRIEF DESCRIPTION OF THE DRAWING The exact nature of this invention will be readily apparent from consideration of the following description relating to the annexed drawing in which:

FIGS. 1A and 1B show the level sensing assembly of the instant invention.

FIGS. 2A and 2B show a top and side view of the signal jet block of FIG. 1.

FIGS. 3A and 3B show a top and side view of the flow interrupting block of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, wherein like reference characters designate like or corresponding parts throughout the several views, there is shown in FIGS. 1A and 1B the level sensing assembly comprising upper block 11 and a lower output block 12. Air under pressure is fed through top channel 13, transverse jets 14 and 15, and through inlets 16 and 17 of the upper channel 18 and a lower channel 19 respectively. Upper outlet 20 and lower outlet 21 are provided for connecting a control or sensing mechanism. Documents or cards 22 are stacked against a wall 23 or other type support. Cut outs 24 and 25 are provided to form breaks in the air flow through channels 18 and 19. Transverse jets 14 and are aligned so that the air coming therefrom (shown as heavy zig-zag lines) interacts in the cut outs 24 and 25 with the air from channels 18 and 19 thereby preventing output signals from appearing at outlets and 21.

In operation, air pressure is supplied to top channel 13 and to upper and lower channels 18 and 19 thereby producing the interaction in cut outs 24 and (as shown by the heavy zigzag lines in FIG. 18) with no output signal at either outlets 20 or 21. Documents 22 are stacked against wall '23, or other suitable support or structure, until the level of documents 22 interrupts the flow of air from transverse jet 14, most easily seen in FIG. 1A, thereby permitting air in channel 19 to pass completely through lower output block 12, that is, from inlet 17 through lower channel 19, thence through out out 24 and continue on through lower channel 19 to lower outlet 21 where a control or sensing means is connected to a stack raising, lowering, or feeding device. If it is desirable to keep the documents 22 between the two upper and lower channels 18 and 19, a control logic may be set up so that the stack of documents 22 would be raised by any suitable means until the documents 22 interrupt the air flow from jet 14 thereby permittin a control signal at outlet 21. The control signal from outlet 1 would then be used to stop the raising of documents 22. Other documents 22 are stacked to a height sufficient to interrupt the air flow from jet 15 thereby producing a control signal at outlet 20, such control signal used to lower the documents until they are lowered to channel 19. The logic would not allow the stack of documents 22 to lower until both jets 14 and 15 were interrupted thereby producing signals at outlets 20 and 21. The stack would then be lowered until the air flow from both jets l4 and 15 was uninterrupted thereby stopping the lowering operation and initiating the raising operation, as heretofore described, and completing the cycle of operation for level control.

There is shown in FIGS. 2A, 2B and 3A, 38 top and side views of the upper block 11 and the lower outlet block 12, respectively, such drawings clearly showing cut outs 24, 25, channels 18, 19, outlets 20, 21, top channel 13 and jets 14 and 15.

Obviously other operations might be performed using the signals from outlets 20 and 21 including the use of multiple sensing channels and outlet ports placed one above the other. Likewise, output signals might be employed to control other operations, e.g. feeding, etc., or other equipment.

It should be understood, of course, that the foregoing disclosure relates to only a preferred embodiment of the invention and that numerous modifications or alterations may be made therein without departing from the spirit and the scope of the invention as set forth in the appended claims:

What is claimed is:

1. A level sensing device comprising:

a support for holding stacked material;

an output block connected to said support, said output block having fluid pressure channels therein, said fluid pressure channels having outlet ports;

an upper block mounted on said output block, said upper block having fluid pressure channels therein, and fluid pressure in all said channels said fluid pressure channels in said upper block being so constructed so as to cause the fluid pressure in the upper block channels to interact with the fluid pressure in the fluid pressure channels in said output block in such a manner that, when the level of said stacked material is at approximately the height of said fluid pressure channels in said output block, a signal is present at said outlet ports.

2. The level sensing device according to claim 1, and further comprising that:

said output block has a series of cut-outs therein where said fluid pressures interact thereby preventing a signal at said outlet ports when said material is below the level of said fluid pressure channels in said output block.

3. In a device for transporting documents, a level sensing assembly comprising;

a support for holding stacked material;

an output block connected to said support, said output block having fluid pressure channels therein positioned one above the other, said fluid pressure channels having outlet ports, said channels passing through said block and interrupted by cut outs, and;

an upper block mounted on said output block, said upper block having fluid pressure channels therein communicating with said cut outs so that when fluid pressure is applied to said channels a signal is present at said outlet ports when the level of said stacked material is at the approximate level of said fluid pressure channels in said outlet block.

l l i 

1. A level sensing device comprising: a support for holding stacked material; an output block connected to said support, said output block having fluid pressure channels therein, said fluid pressure channels having outlet ports; an upper block mounted on said output block, said upper block having fluid pressure channels therein, and fluid pressure in all said channels said fluid pressure channels in said upper block being so constructed so as to cause the fluid pressure in the upper block channels to interact with the fluid pressure in the fluid pressure channels in said output block in such a manner that, when the level of said stacked material is at approximately the height of said fluid pressure channels in said output block, a signal is present at said outlet ports.
 2. The level sensing device according to claim 1, and further comprising that: said output block has a series of cut-outs therein where said fluid pressures interact thereby preventing a signal at said outlet ports when said material is below the level of said fluid pressure channels in said output block.
 3. In a device for transporting documents, a level sensing assembly comprising; a support for holding stacked material; an output block connected to said support, said output block having fluid pressure channels therein positioned one above the other, said fluid pressure channels having outlet ports, said channels passing thrOugh said block and interrupted by cut outs, and; an upper block mounted on said output block, said upper block having fluid pressure channels therein communicating with said cut outs so that when fluid pressure is applied to said channels a signal is present at said outlet ports when the level of said stacked material is at the approximate level of said fluid pressure channels in said outlet block. 